Sanders comments came a day after excerpts were published from Clinton’s upcoming campaign memoir, “What Happened.” In the book, Clinton claims that the “attacks” Sanders leveled at her during the 2016 Democratic primary “caused lasting damage,” made it harder to “unify progressives” and paved the way for Trump’s “Crooked Hillary” refrain during the general election.

“I don’t know if that bothered Bernie or not,” Clinton writes. “He certainly shared my horror at the thought of Donald Trump becoming President, and I appreciated that he campaigned for me in the general election. But he isn’t a Democrat.”

Sanders lost his bid for the Democratic nomination and endorsed Clinton two weeks before the Democratic National Convention.

“He didn’t get into the race to make sure a Democrat won the White House,” Clinton continues. “He got in to disrupt the Democratic Party.”

And while Sanders “was right Democrats needed to strengthen [their] focus on working families” and engage younger voters, “he was fundamentally wrong about the Democratic Party,” Clinton argues, ticking off a list of Democrat-led accomplishments including Social Security, Middle East peace, the auto industry bailout and health care reform.